/*

  $Id: rlp-crc24.c,v 1.7 2005/04/20 20:30:18 pkot Exp $

  G N O K I I

  A Linux/Unix toolset and driver for the mobile phones.

  This file is part of gnokii.

  Gnokii is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  Gnokii is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with gnokii; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  Copyright (C) 1999-2000  Hugh Blemings & Pavel Janík ml.
  Copyright (C) 2001-2004  Pawel Kot
  Copyright (C) 2002-2004  BORBELY Zoltan

  CRC24 (aka FCS) implementation in RLP.

*/

#include "rlp-crc24.h"

/* CRC-24 table is used for computation of RLP checksum. */

const u32 CRC24_Table[256] = {
	0x00000000, 0x00D6A776, 0x00F64557, 0x0020E221, 0x00B78115, 0x00612663,
	0x0041C442, 0x00976334, 0x00340991, 0x00E2AEE7, 0x00C24CC6, 0x0014EBB0,
	0x00838884, 0x00552FF2, 0x0075CDD3, 0x00A36AA5, 0x00681322, 0x00BEB454,
	0x009E5675, 0x0048F103, 0x00DF9237, 0x00093541, 0x0029D760, 0x00FF7016,
	0x005C1AB3, 0x008ABDC5, 0x00AA5FE4, 0x007CF892, 0x00EB9BA6, 0x003D3CD0,
	0x001DDEF1, 0x00CB7987, 0x00D02644, 0x00068132, 0x00266313, 0x00F0C465,
	0x0067A751, 0x00B10027, 0x0091E206, 0x00474570, 0x00E42FD5, 0x003288A3,
	0x00126A82, 0x00C4CDF4, 0x0053AEC0, 0x008509B6, 0x00A5EB97, 0x00734CE1,
	0x00B83566, 0x006E9210, 0x004E7031, 0x0098D747, 0x000FB473, 0x00D91305,
	0x00F9F124, 0x002F5652, 0x008C3CF7, 0x005A9B81, 0x007A79A0, 0x00ACDED6,
	0x003BBDE2, 0x00ED1A94, 0x00CDF8B5, 0x001B5FC3, 0x00FB4733, 0x002DE045,
	0x000D0264, 0x00DBA512, 0x004CC626, 0x009A6150, 0x00BA8371, 0x006C2407,
	0x00CF4EA2, 0x0019E9D4, 0x00390BF5, 0x00EFAC83, 0x0078CFB7, 0x00AE68C1,
	0x008E8AE0, 0x00582D96, 0x00935411, 0x0045F367, 0x00651146, 0x00B3B630,
	0x0024D504, 0x00F27272, 0x00D29053, 0x00043725, 0x00A75D80, 0x0071FAF6,
	0x005118D7, 0x0087BFA1, 0x0010DC95, 0x00C67BE3, 0x00E699C2, 0x00303EB4,
	0x002B6177, 0x00FDC601, 0x00DD2420, 0x000B8356, 0x009CE062, 0x004A4714,
	0x006AA535, 0x00BC0243, 0x001F68E6, 0x00C9CF90, 0x00E92DB1, 0x003F8AC7,
	0x00A8E9F3, 0x007E4E85, 0x005EACA4, 0x00880BD2, 0x00437255, 0x0095D523,
	0x00B53702, 0x00639074, 0x00F4F340, 0x00225436, 0x0002B617, 0x00D41161,
	0x00777BC4, 0x00A1DCB2, 0x00813E93, 0x005799E5, 0x00C0FAD1, 0x00165DA7,
	0x0036BF86, 0x00E018F0, 0x00AD85DD, 0x007B22AB, 0x005BC08A, 0x008D67FC,
	0x001A04C8, 0x00CCA3BE, 0x00EC419F, 0x003AE6E9, 0x00998C4C, 0x004F2B3A,
	0x006FC91B, 0x00B96E6D, 0x002E0D59, 0x00F8AA2F, 0x00D8480E, 0x000EEF78,
	0x00C596FF, 0x00133189, 0x0033D3A8, 0x00E574DE, 0x007217EA, 0x00A4B09C,
	0x008452BD, 0x0052F5CB, 0x00F19F6E, 0x00273818, 0x0007DA39, 0x00D17D4F,
	0x00461E7B, 0x0090B90D, 0x00B05B2C, 0x0066FC5A, 0x007DA399, 0x00AB04EF,
	0x008BE6CE, 0x005D41B8, 0x00CA228C, 0x001C85FA, 0x003C67DB, 0x00EAC0AD,
	0x0049AA08, 0x009F0D7E, 0x00BFEF5F, 0x00694829, 0x00FE2B1D, 0x00288C6B,
	0x00086E4A, 0x00DEC93C, 0x0015B0BB, 0x00C317CD, 0x00E3F5EC, 0x0035529A,
	0x00A231AE, 0x007496D8, 0x005474F9, 0x0082D38F, 0x0021B92A, 0x00F71E5C,
	0x00D7FC7D, 0x00015B0B, 0x0096383F, 0x00409F49, 0x00607D68, 0x00B6DA1E,
	0x0056C2EE, 0x00806598, 0x00A087B9, 0x007620CF, 0x00E143FB, 0x0037E48D,
	0x001706AC, 0x00C1A1DA, 0x0062CB7F, 0x00B46C09, 0x00948E28, 0x0042295E,
	0x00D54A6A, 0x0003ED1C, 0x00230F3D, 0x00F5A84B, 0x003ED1CC, 0x00E876BA,
	0x00C8949B, 0x001E33ED, 0x008950D9, 0x005FF7AF, 0x007F158E, 0x00A9B2F8,
	0x000AD85D, 0x00DC7F2B, 0x00FC9D0A, 0x002A3A7C, 0x00BD5948, 0x006BFE3E,
	0x004B1C1F, 0x009DBB69, 0x0086E4AA, 0x005043DC, 0x0070A1FD, 0x00A6068B,
	0x003165BF, 0x00E7C2C9, 0x00C720E8, 0x0011879E, 0x00B2ED3B, 0x00644A4D,
	0x0044A86C, 0x00920F1A, 0x00056C2E, 0x00D3CB58, 0x00F32979, 0x00258E0F,
	0x00EEF788, 0x003850FE, 0x0018B2DF, 0x00CE15A9, 0x0059769D, 0x008FD1EB,
	0x00AF33CA, 0x007994BC, 0x00DAFE19, 0x000C596F, 0x002CBB4E, 0x00FA1C38,
	0x006D7F0C, 0x00BBD87A, 0x009B3A5B, 0x004D9D2D
};

void rlp_crc24polinomial_calculate(u8 *data, int length, u32 *polinomial)
{

	int i;
	u8 cur;

	*polinomial = 0x00ffffff;

	for (i = 0; i < length; i++) {
		cur = (*polinomial & 0x0000ffff) ^ data[i];
		*polinomial = (*polinomial >> 8) ^ CRC24_Table[cur];
	}

	*polinomial = ((~*polinomial) & 0x00ffffff);
}


void rlp_crc24checksum_calculate(u8 *data, int length, u8 *crc)
{
	u32 polinomial;

	rlp_crc24polinomial_calculate(data, length, &polinomial);
	crc[0] = polinomial & 0x0000ffff;
	crc[1] = (polinomial >> 8) & 0x0000ffff;
	crc[2] = (polinomial >> 16) & 0x0000ffff;

}

bool rlp_crc24fcs_check(u8 *data, int length)
{

	u8 crc[] = { 0x00, 0x00, 0x00 };

	rlp_crc24checksum_calculate(data, length - 3, crc);

	if (((data[length - 3] == crc[0]) &&
		(data[length - 2] == crc[1]) &&
		(data[length - 1] == crc[2]))) {
		return (true);
	}
	return (false);
}